In addition to the radial dependence of the metal abundances, important information can be inferred also from the azimuthal substructure revealed by 2D maps; typically these are of course only available for very deep observations of the brightest systems. Early work by [1]} presented a systematic analysis of the metallicity distribution in NGC5846, NGC4636, and NGC5044 using XMM-Newton. It was shown that, while the profiles are consistent with a linear decrease with radius, the scatter of the data points was as high as 30-50%. This pointed towards a patchiness of the 2D metal abundance using typical spatial resolution elements of 2 – 10 kpc, which cannot be explained solely by the satellite subhaloes. Later studies revealed that, very generally speaking, the main physical mechanisms responsible for such a 2D metallicity substructure are related either to AGN feedback or to ongoing mergers.
